1st Gen R53 Cooper S Most liked posts in thread: Headwork - general discussion 2.0

cct1 replied:

Thanks Blimey, that's a nice read.

So there's as much of an art as their is a science to these things, at least in the porting--what you'd intuitively think would increase airflow may not on the flowbench. And some of the stuff Mike's been writing about valves now is making senses--maybe it's the lack of bold faced type, I dunno..



Questions:

1. So is everyone doing heads using a flowbench? I'm assuming they are. Anyone game enough to put some numbers up, and more importantly, explain them?


2. "As valves and seats wear, they tend to sink lower into the seats creating seating surface mismatches and valve shrouding (partial blockage or restriction caused by objects in close proximity of the valve seat; imagine having the valve having to lift itself out of a deep crater before it can start to flow). Wide seating surfaces tend to last a little longer when the valves sink under wear."

So it looks like this means a high performance valve job is going to be less durable over the long term than the stock valves, but it also looks like there are ways to improve durability--so what options are available to increase durability--what are each of the head makers doing in this regard, and are their "upgrades" available if we choose to shell out the extra cash that may prove worthwhile for those of us planning on holding on to our car until we die?

3. Which machine is everyone using for grinding valves? I suspect there's a wide variance of what people are using, and I suspect the ensuing discussion will be roughly as contentious as the CNC discussion was, but what the hell, I'm here to learn...

4. Anybody doing anything with "quench" zones, or are they even that important in the Tritech? Admittedly engines are way outside my universe, but this is the first I've ever seen "quench zones" mentioned.


Seems like the MINI head can't be THAT bad to begin with--although I still will get mine done, the gains, while there, aren't nearly close to the 50-100 HP gains quoted in the article on the domestics, meaning (I assume) that there is less to improve upon to begin with.

Anyway, nice article, thanks for posting it!

 

Thumper460 replied:

Quote:
Originally Posted by BlimeyCabrio
Since heads have become an off-topic topic of a number of threads, I thought it would be fun to have a thread dedicated to headwork discussion so we can then turn it into a thread about cams or suspension or something like that.

Ground rules: this isn't a thread for pitching whatever head you're selling. But it IS a thread for discussing pros and cons of different approaches to headwork, trade-offs of various types of head improvements, and general education of the unwashed masses on how and why headwork works.

It is some times thought that when a person with knowledge, posts the good/bad/ugly of a product... and this person also sells simular product, that he is selling HIS Product! And because of this, there are sites that will edit, or even ban the person. Some vender's are "selling " stuff that works, however it is a business, others are MAKING the product and their philosophy, technique and results, are sometime thought to be SALES... when actually IT IS Passing Knowledge. Yes??
I would LOVE to add my answers to this... but, I doubt if I could cause it will "seem like I am pushin my stuff" !


To kick it off, I found this very good article this morning. Required reading for anyone who wants to participate in the discussion. Otherwise I'll call you out and say bad things about your momma.

Secrets of the Cylinder Head - Tech - Sport Compact Car Magazine
I thought this did a particularly good job of describing the art and science of valve jobs, of which I previously had a poor understanding. But it also covers porting in general, and flow vs. velocity considerations.
Quote:
Originally Posted by cct1
Thanks Blimey, that's a nice read.

So there's as much of an art as their is a science to these things, at least in the porting--what you'd intuitively think would increase airflow may not on the flowbench. And some of the stuff Mike's been writing about valves now is making senses--maybe it's the lack of bold faced type, I dunno..
Questions:

1. So is everyone doing heads using a flowbench? I'm assuming they are. Anyone game enough to put some numbers up, and more importantly, explain them?
]Flow bench is a tool!! and this tool can be misunderstood.. GREATLY misunderstood! Therefore as a tool for buying a head.. I'd rather us the results from guys that USE the Product.

2. "As valves and seats wear, they tend to sink lower into the seats creating seating surface mismatches and valve shrouding (partial blockage or restriction caused by objects in close proximity of the valve seat; imagine having the valve having to lift itself out of a deep crater before it can start to flow). Wide seating surfaces tend to last a little longer when the valves sink under wear."
True... how ever the amount in these heads ( seat and Valve) isnt going to be ANY issue at all!! None.. Nada.. Nix!!

So it looks like this means a high performance valve job is going to be less durable over the long term than the stock valves, but it also looks like there are ways to improve durability--so what options are available to increase durability--what are each of the head makers doing in this regard, and are their "upgrades" available if we choose to shell out the extra cash that may prove worthwhile for those of us planning on holding on to our car until we die?

In the valve job... it is all in the thickness and where Placed the seat( interface) is! You can gain performance and retain the durability if done correct!

3. Which machine is everyone using for grinding valves? I suspect there's a wide variance of what people are using, and I suspect the ensuing discussion will be roughly as contentious as the CNC discussion was, but what the hell, I'm here to learn...

The tool for cutting the seats is all in the hand of the machinist!! Multi-angles can be accomplished with an experienced Grinder.[/COLOR]
4. Anybody doing anything with "quench" zones, or are they even that important in the Tritech? Admittedly engines are way outside my universe, but this is the first I've ever seen "quench zones" mentioned.
Explain??


Seems like the MINI head can't be THAT bad to begin with--although I still will get mine done, the gains, while there, aren't nearly close to the 50-100 HP gains quoted in the article on the domestics, meaning (I assume) that there is less to improve upon to begin with.

working with a 1.6 ltr.. 100 HP gains is quite common!! LOL More like a 20-35 HP bolt on. However when tuned, and all the other performance items are added.... the HEAD ( along with the camshaft) tie it all together!!

The stock Head on the MINI is totally a fantastic Product!! The r56 turbo is flat ass rocking!! However there is ALWAYS more power in there.
Anyway, nice article, thanks for posting it!

No matter what someone says about HUGE Valves... Huge cams... Huge Runner CC's.... You should always get real with your goals and Performance needs!! Cool??

Just me.................................

Thumper
__________________
THUMPER Performance
.........The OTHER MINI Head!


"Worlds Fastest MINI on a S/C !!"
Car is NOW at 11.16 ET at 123.4 MPH!!
(uses the TPR-2 Ported Head!)

Thumper Performance | The OTHER MINI Head!

 

Minidave replied:

I've read that the exhaust side of the MINI head works really well right out of the box, and that most improvemnts to the stock head come on the intake side?

Comments from those who know?

 

Thumper460 replied (with some attached images):

exhaust..
Boosted engine.. exhaust is the "more important" on the n/a engine Velocity is the key.

Here is a stock exhaust... and one being worked on!

Just me..........................

Thumper

 

Dr Obnxs replied:
That's backwards...
exhaust needs help, intake can do pretty well.

A comment on the gains from headwork. Think of it in percentages, not absolute numbers. So quotes of HP gains on a 350 cu in engine aren't going to happen on our little 1.6 liter engines.

Materials technology has come a very long way. There are reasons why it's not uncommon to hear of engines lasted 100k-200k or more when treated well. We've come a long way from the days of getting more than 75k out of an engine without a rebuild (that was pretty common when I first took auto shop).

And I totally agree with thumper on a couple of things: One is that someone who really knows what they are doing will do very good work with a relatively primative valve grinding set up.

When it comes to port size/volume and the like, this is all standard stuff and isn't new when it comes to our little engines. Velocity vs flow has a direct analogy to exhaust sizing... huge pipes flow more but the drop in velocity can have negative effects. Once again, there is no "best" there is just what's well mated to the use application. This is where working closely with whomever is doing your porting is important, cause what works best in one use case is exactly wrong in another use case.

From the 60s, there was a Ford engine called the 351 cleveland. One version (for the 4 barrel carb) came with HUGE port volume. It was so big that the head was loved by racers, but the street crowd use "port plates" that made the port volume much less so that the bottom end made much more torqure.

Also, the article seems a bit dated. While it's true that the domestics were milking some older engine designs, that has been less and less true over the last 5-10 years. Ford went to multi-valve OHC designe earlier than other domestics, but you can bet your left nut that the port geometry is a very well optimized implementation in the last few GM small blocks to get the HP/CI that they have been getting. These Corvette (and all thier derivitives) engines are really a marvel of engineering for "stone age" pushrod designs. Now pretty much all the domestics (even Chrysler is getting into the game) are going high effeciency engine designs, and the notion that the port geometry is left for last is really a thought that died in the 90s or so.

If you want to know more about quench and knock, hunt around on the Endyn site. There are some really good tech notes there that go into the subject.

Overall, the article does a good job saying "there's power to be had, and don't forget a good valve job!" and "watch out for the trade-offs" but it doesn't go at all into swirl and tumble, a couple of things that promote better air-fuel mixing and the like. I also think that for the aftermarket, there is more art than science, but for the real engine manufacturers, you can bet your remaining right nut that some very serious computational fluid dynamics simulation software is used to do virtual desing optimization. It's just that those tools are way out of reach of the average tuner shop.

matt

 

I replied:

Quote:
Originally Posted by Thumper460
It is some times thought that when a person with knowledge, posts the good/bad/ugly of a product... and this person also sells simular product, that he is selling HIS Product! And because of this, there are sites that will edit, or even ban the person. Some vender's are "selling " stuff that works, however it is a business, others are MAKING the product and their philosophy, technique and results, are sometime thought to be SALES... when actually IT IS Passing Knowledge. Yes??
I would LOVE to add my answers to this... but, I doubt if I could cause it will "seem like I am pushin my stuff" !
I think we can stay on the "non-product-pitching" side of the line pretty successfully.

It's perfectly fine to include here some of the discussion that was happening on the other thread about the relative strengths of various heads. NO problem with hearing vendors talk about the approaches and techniques they have seen work - I would certainly hope vendors would be passionate about their approach, and why it makes for a good head.

As long as we leave out the part that says "you should buy a Brand T/E/R/whatever head because it's just plain better....". But I'm OK with "Brand T heads are great because they have features A, B and C".

Let's just keep it civil, and let's keep the positioning oriented toward education vs. selling. I believe well educated consumers make good decisions (for them) based on their requirements. Better educated consumers will equal more quality heads sold by most or all of the vendors discussed.

I for one delayed my head purchase for quite a while in part because I just plain didn't understand what my options were, how I should determine my requirements, what i should expect if I put a head on my car, how this complex voodoo part actually worked, what the pros and cons were of various approaches, etc. Let's help remove that uncertainty for some future buyers.

 

Dr. O replied:

Time for some heresy....
if anyone really wants to start learning about performance engine building and tuning, the internet is the worst place to go. Good information is there, but it's hard to find and diluted with tons of total BS. If you really want to learn about performance engine building, start with a book. Learn about the basic concepts that are applicable to pretty much all engines and the like, and once one has the basic concepts down, then learn about the particulars of the car you care about. For this forum that would be the MINI.

Pretty much every thread on Mini forums I've ever participated in on things like exhaust, cams, heads, intakes, intercoolers, crank pulleys WHATEVER, have had a low content to words ratio, and lots of mis-information in them.

Anyway, back to our normally scheduled thread content.

Matt

 

CFMINI replied:

Dig into Endyn's web site - The Old One - Energy Dynamics Piston shape is very important too, not just the head side. And off topic, the new section on Grand Sport Corvettes is fantastic!!

 

Then, unfortunately, a page of posts was lost - I was unable to find these in cache.

 

Then Thumper460 replied (with some attached dyno plots - maybe he can repost these):

We (I) have seen a power increase of 22-28 WHP gain when bolting a Ported (TPR-1)
Head on stock engine, stock ECU, supporting only a pulley/CAI. Add more mods will only allow more power..

As Dr O said... I agree.. the newer Heads of today are far superior to the early V8 Heads, even the 4 cyl. heads!! Multi valves, straighter runners, better throats and bowls all add to this. To figure that you will have huge gains with JUST a modified head is incorrect. ( although 22 WHP is about the same as adding a SC pulley upgrade)

But also as stated by CCT1.... the head design is very good!! If you really want to get excited.. take a look at the DOHC r56 Turbo Head!! Talk about good design!! (yes, there is more power to be made in that head also...). When doing mods... it is always best to let the money and common sense rule!! Air in... air out!! Raise the Boost ( keeping in relationship to the ECU).. then enhance that power!! Head and cam!
However.. installing JUSTA Head, or Justa Cam, will STILL show a power increase!!
Like all mods... the power gains are all pulled together with the Tune ( to correct the ECU for the current mods).

By the way... on the r50 MINI, there are power increases also with a proper Head and or a Head /Cam combo. Finally as the need for this stuff is becoming apparent.. parts are being made for more applications!! SOOooooo... a LOT of the older ideas and thoughts of befor , are no longer applicable!! cool??

Just me................................

Thumper

PS: Keep in mind these are Stock ECU's Tks

 

racingheads replied:

Since this is discussion on educating members of the forum, we would like to see more questions.

The four of us on this group, all have experience in modifying cylinder heads. Our research in how we approach each opportunity is based on the customers needs for performance.

We are not in competition with each other, we are here to share what we have learned with others.

 

Jason Montague replied:

Love to. But I'm to stupid to know what to ask.Jason

 

racingheads replied:

There is no such thing as a stupid question.
Lets say as a customer, your goal is, I want to increase my car's power within my budget, what would I do?
Using a package of the following, modified cylinder head, stock cam, hedder and cat back exhaust, pulley mods for 18 psi boost, new horsepower 50 plus. ( 220 hp.) Add a performance camshaft at a later time, up's it to 240 hp, slight pcm mods.

 

I replied:

OK - I'll bite - and maybe Dr. O can chime in here with his thoughts, too.

Given that OEM heads have improved greatly in the past few decades, with more advanced design (fluid dynamics modeling) and manufacturing techniques... are handwork and related cost the only reason OEM heads aren't "better"?

I understand most things are a matter of trade-off decisions - but it also seems that some relatively "mild" reworked heads actually seem better at just about everything - better or equal fuel economy, better or equal low-end torque, no change to idle manners, and significant mid-range to high-end torque gains.

Just seems like if there were really several HP an TQ available to be had with no downside, the manufacturers would find a way to automate this...

 

... and that's all I could retrieve from the cache.

Any help in rebuilding some of the great discussion we had going here is appreciated!